Ring clamps are usually fixed on filing appliances or notebooks. When the ring clamp is in the opened state, perforated loose-leaf paper can be added or removed. When the ring clamp is in the closed state, the loose-leaf paper is sleeved into rings of the ring clamp and can turn over along the rings.
The Chinese patent titled “ring clamp structure” (the patent application number: 200710129155.5) discloses a ring structure for retaining loose-leaf paper, which comprises a housing and articulated plates which are supported by the housing to perform pivoting movement relative to the housing, wherein ring members are mounted on the articulated plates and can move between closed positions and opened positions; an actuator is mounted on the housing and configured to move relative to the housing, so that the pivoting movement of the articulated plates can be achieved; locking members are configured to lock the released and closed ring members at locking positions, and the released and closed ring members are driven to move to opened positions of unlocked positions; and an intermediate connector is configured to operably connect the locking members to the actuator and can be deformed during the movement of the actuator.
When the ring members are closed, an upper lip section of a control handle of the actuator is connected with inner surfaces of the articulated plates; the articulated plates are pulled down, but the elasticity of the housing resists the initial movement of the articulated plates. In addition, a moving rod of the intermediate connector can initially move forwards along with the movement of the upper lip section, so that front edges of the locking members abut against projections of the articulated plates; when the control handle is pivoted continuously, the abutted locking members prevent the moving rod from moving further; a flexible hinge of the intermediate connector begins to be curved, so that the control handle can be pivoted continuously; and due to the relative movement between a connector section of the intermediate connector and the locking members, the tension is generated by the flexible hinge. Once the articulated plates cross the oblique front edges of the locking members, the forward movement of the locking members and the moving rod cannot be resisted again; and at this point, the locking members move to the locking positions thereof behind the articulated plates along with the control handle.
The above patent utilizes the tension generated by the deformation of the intermediate connector to push the locking members to the locking positions, and has the defects that: as each closing action of the ring clamp structure needs to overcome the tension generated by the deformation of the intermediate connector so as to close a ring clamp, the closing action is laborious and the ring clamp is inconvenient to use.